U.S. patent application number 11/571777 was filed with the patent office on 2009-02-26 for arrangement for injecting and affixing a reinforcing or anchoring element in a rock wall.
This patent application is currently assigned to ATLAS COPCO CRAELIUS AB. Invention is credited to Jan Eriksson, Sten-Ake Petersson.
Application Number | 20090052995 11/571777 |
Document ID | / |
Family ID | 32823011 |
Filed Date | 2009-02-26 |
United States Patent
Application |
20090052995 |
Kind Code |
A1 |
Eriksson; Jan ; et
al. |
February 26, 2009 |
Arrangement for injecting and affixing a reinforcing or anchoring
element in a rock wall
Abstract
The present invention relates to an arrangement and to a method
for injecting and affixing a reinforcing and/or anchoring element
in a rock wall. The arrangement includes means (15; 65) for
connection to a reinforcing and/or anchoring element (2; 62), an
injection pipe (9) which is connected to the coupling means at a
front end facing inwardly in the hole and which includes means (7)
for connection to means for supplying injection medium (8). The
arrangement also includes a check valve (10) for co-action with the
injection medium, and an expandable seal (10; 50; 60). The
arrangement is designed as a separate unit that can be loosened
from the reinforcing and/or anchoring element upon completion of
the injection phase. The method comprises corresponding process
steps.
Inventors: |
Eriksson; Jan; (Kista,
SE) ; Petersson; Sten-Ake; (Stenhamra, SE) |
Correspondence
Address: |
GREENBERG TRAURIG, LLP
2101 L Street, N.W., Suite 1000
Washington
DC
20037
US
|
Assignee: |
ATLAS COPCO CRAELIUS AB
Marsta
SE
|
Family ID: |
32823011 |
Appl. No.: |
11/571777 |
Filed: |
July 7, 2005 |
PCT Filed: |
July 7, 2005 |
PCT NO: |
PCT/SE2005/001133 |
371 Date: |
October 21, 2008 |
Current U.S.
Class: |
405/259.5 |
Current CPC
Class: |
E21D 21/0046 20130101;
E21D 20/028 20130101 |
Class at
Publication: |
405/259.5 |
International
Class: |
E21D 20/02 20060101
E21D020/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 8, 2004 |
SE |
0401806-5 |
Claims
1. An arrangement for injecting and affixing a reinforcing and/or
anchoring element in a hole in a rock wall, wherein the arrangement
includes a means for connection to a reinforcing and/or anchoring
element, an injection pipe which is connected to said coupling
means at a front end facing in towards the hole and which also
includes means for connection to an injection medium supply means,
wherein the arrangement also includes a check valve for co-action
with the injection medium and an expandable seal characterized in
that the arrangement consists of a separate unit that can be
released from the reinforcing and/or anchoring element upon
completion of the injection phase.
2. An arrangement according to claim 1, characterized in that the
coupling means includes an internally threaded coupling for
connection with an externally threaded end of the reinforcing
and/or anchoring element.
3. An arrangement according to claim 1, characterized in that the
coupling means and the injection pipe comprise a single entity.
4. An arrangement according to claim 1, characterized in that the
coupling means is designed to facilitate release from the
surrounding injected material upon completion of the injection
phase and subsequent to hardening of said material.
5. An arrangement according to claim 1, characterized in that the
arrangement can be re-used.
6. An arrangement according to claim 1, characterized in that the
seal has the form of a sleeve disposed around the injection
pipe
7. An arrangement according to claim 6, characterized in that the
seal has the form of a mechanically expandable sleeve.
8. An arrangement according to claim 6, characterized in that the
seal has the form of a sleeve that includes double walls and that
can be expanded by injecting pressurized medium in between said
walls.
9. An arrangement according to claim 8, characterized in that the
arrangement includes means for delivering pressurized medium to the
seal.
10. An arrangement according to claim 1, characterized in that the
check valve is located in the front end of the injection pipe.
11. An arrangement according to claim 1, characterized in that the
coupling means has an axially extending through-penetrating
aperture or bore and is designed to enable it to be coupled to a
tubular element forming said reinforcing and/or anchoring element,
and in that the check valve regulates the supply of injection
medium from the injection pipe via the aperture in the coupling
means, and through said tubular element and out at the front end of
said element.
12. An arrangement according to claim 11, characterized in that the
tubular element forming said reinforcing and/or anchoring element
is a drill rod which has an internal channel and which is provided
with a drill bit for drilling said hole, and in that said check
valve regulates the supply of injection medium from the injection
pipe via the aperture in the coupling means, and through said drill
rod and out through the drill bit.
13. A method of injecting and affixing a reinforcing and/or
anchoring element in a rock wall, said method comprising the steps
of: inserting in a hole in the rock wall a reinforcing and/or
anchoring element coupled to an injection arrangement which
constitutes a separate unit and which includes means for connection
to a reinforcing and/or anchoring element, an injection pipe which
is connected to said coupling means at a front end facing inwardly
in the hole and which includes means for connection to an injection
medium supply means, wherein the arrangement also includes a check
valve for co-action with the injection medium, and an expandable
seal, expanding the seal of the injection arrangement, said seal
being able to prevent injection medium injected into the hole from
flowing out of the hole during and after the injection phase,
delivering injection medium to the hole via said injection
arrangement and said check valve, terminating the injection phase
and allowing the injection medium to harden, causing the expandable
seal to return to its non-expanded state upon completion of the
injection phase and after at least partial hardening of the
injection medium, and removing the injection arrangement as a
unit.
14. A method according to claim 13, characterized by drilling the
hole with the aid of a drill rod provided with a drill bit, said
drill rod later forming said reinforcing and/or anchoring element;
and by drilling said hole when the injection arrangement has
already been coupled to the reinforcing and/or anchoring
element.
15. A method according to claim 14, characterized by carrying out
said injection phase through the medium of a through-penetrating
aperture in the coupling means, and via an internal channel in the
drill rod and out into the hole via the drill bit fitted to the
front end of the drill rod.
16. A method according to claim 13, characterized by injecting the
injection medium at an overpressure, wherewith the hole is first
filled with injection medium which thereafter penetrates into any
cracks that may be present in the rock and that open out into the
hole, therewith sealing the cracks.
17. A method according to claim 13, characterized by reusing the
injection arrangement for injecting and affixing a new reinforcing
and/or anchoring element in said rock wall.
18. A method according to claim 13, wherein a free end of the
reinforcing and/or anchoring element will remain in the hole sealed
with said injection medium subsequent to removal of the injection
arrangement, this free end being used for the attachment of further
equipment.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an arrangement and a method
for affixing reinforcing and/or anchoring elements in rock walls in
accordance with the preamble of claim 1 and in accordance with
claim 13.
BACKGROUND OF THE INVENTION
[0002] Work on and in rock walls often results in problems relating
to crack formations, the danger of rock slides or rock slips and
other hazards that make it necessary to reinforce the rock wall.
For example, such problems may occur in the building of tunnels or
rock cavities, and may also apply to open-air rock walls in the
construction of roads, highways and the like. In such cases
reinforcement is most often achieved with the aid of different
methods in which reinforcement elements, normally in the form of
reinforcing rods or reinforcement rounds or the like anchored in
holes drilled in the rock wall. So-called rockbolts and roof bolts
are examples of reinforcing and/or anchoring elements.
[0003] A well known and simple method of affixing reinforcement
elements in a rock wall involves firstly the injection of cement or
like material into a hole in the rock wall. This hole may be an
already existing hole in the rock wall, although the hole will be a
separately pre-drilled hole in the majority of cases. A reinforcing
element is then inserted into the cement, whereafter the entire
cement package is allowed to harden. As the cement hardens it will
shrink somewhat and because there is no other form of anchorage in
the rock wall than that afforded by the adhesion of the cement to
the rock face, there is often the danger that the entire
cement-"plug", including the reinforcement element, will loosen and
at times even fall out of the hole.
[0004] Another problem experienced when working with and in rock
walls is that moisture and water may obtain ingress through cracks
for instance, which often results in the need to seal such cracks.
When holes are drilled for the reinforcement of rock walls as
described above, leakages also often occur as a result of
puncturing the natural screen that was present prior to drilling. A
punctured screen is often sealed by injecting some kind of sealing
agent into the drilled holes. One example of such a sealing agent
is cement grout or concrete injected into the hole. However, these
sealants are not able to penetrate out into the actual cracks and
consequently the leakage problems remain in many instances. Another
method of sealing the rock is to cover the entire inner surface of
the rock wall with concrete or some other suitable material for
instance.
[0005] Neither is it permitted to secure reinforcing bolts in
water-conducting holes in several instances, but that it must first
be ensured that the hole is dry before securing such bolts.
[0006] The insertion of a sealing agent or filler in a rock-wall
hole is often carried out with the aid of a so-called packer. A
packer typically includes a tubular part fitted to the end of a
tubular drill bit or to a conduit for delivering some type of
sealant, and an expandable cuff, made for instance of a rubber-like
material, is disposed on the tubular part. When the cuff is caused
to expand, the packer will be held firmly to the inner surface of
the hole by friction, and therewith seal against the walls of the
hole. The sealant subsequently injected into the hole is thus
unable to run out while still in a liquid state, provided that the
packer remains seated in the hole.
[0007] Prior publication WO 99/56001 teaches an arrangement for
reinforcing and sealing a rock wall, said arrangement comprising a
reinforcing rod that is connected to an injection element that
includes an injection pipe and a check valve. The reinforcement rod
is permanently connected to the check valve and is inserted into a
pre-drilled hole together with the injection element. The rod is
anchored in the hole and an expandable seal ensures that injected
material is unable to run back out of the hole and the injection
material is injected into the hole via the injection pipe and a
check valve, wherein the check valve includes a cuff that prevents
injection material being pressed back via the valve. The injection
phase is effected at an overpressure, wherewith injection material
shall also be capable of penetrating any possible cracks that open
into the hole. Cement and concrete are mentioned as examples of
injection material. The seal is expanded by tightening a nut
disposed beneath the seal and therewith compress the seal, via a
washer or like device. The nut and the washer can be removed upon
completion of the injection phase and after the material has
hardened, wherewith the seal is allowed to return to its
non-expanded state, whereafter the seal may also be removed.
Remaining parts of the arrangement are left permanently in the
drilled hole on the other hand. One drawback with this known
arrangement is that it cannot be re-used and is therefore
expensive. Another drawback is that there is always a risk of
corrosion attack in the space that remains in the lower part of the
hole after having removed the seal, nut and washer, despite
subsequently filling the space with a filling material, due to the
fact that parts of the injection device still remain in the
hole.
[0008] In such cases there is also a need of fixating in the rock
anchoring devices which enable other devices to be secured in or to
the rock wall. This may apply, for instance, to affixing rockbolts,
affixing reinforcement nets in the case of injection processes,
affixing a protective net to prevent loose pieces of rock or stones
from falling down onto a road surface or somewhere else, providing
a suspension point for different devices and elements used in
mining and tunnelling practices, affixing ventilation equipment
comprising fans, blowers and ducts, channels/drums for other
purposes, lighting, etc.
SUMMARY OF THE INVENTION
[0009] The aim of the present invention is to provide an
arrangement and a method which will resolve these problems and
satisfy the needs mentioned above. This aim is achieved by means of
an arrangement that has the novel features set forth in the
characterising clause of the accompanying claim 1, and by means of
a method that has the characterising features set forth in claim
13.
[0010] Thus, the inventive arrangement comprises a coupling which
is connected to a reinforcing and/or anchoring element, and an
injection pipe which is connected to the coupling means at a front
end that faces inwardly in the hole and which is also provided with
connecting means for connection to an injection medium supply
means, wherein the arrangement also includes an injection medium
check valve and an expandable seal, and wherein the invention is
characterized in that the arrangement has the form of a separate
unit that can be disengaged from the reinforcing and/or the
anchoring element upon completion of the injection phase.
[0011] The advantage afforded by this arrangement is that solely
the end of the reinforcing and/or the anchoring element is exposed
within the hole, and no other parts remain. An additional advantage
is that it is much simpler to seal-off the remaining hole and the
end of the reinforcing and/or the anchoring element than is
possible in the case of the earlier known technique, by injecting
some type of filler into the hole subsequent to completion of the
injection phase. This greatly reduces the risk of corrosion attack.
Alternatively, it may be elected not to fill the remaining part of
the hole with filler and, instead, obtain the advantage of being
able to use the free end of the reinforcing/anchoring element in
the hole as an anchorage and securing point for diverse equipment.
Examples of such equipment have already been mentioned above.
[0012] Another advantage afforded by constructing the injection
arrangement as a separate unit is that it can be removed from the
hole upon completion of the injection phase so as to enable it to
be re-used in a new hole, even repeatedly. The invention thus
affords significant cost savings. A particularly beneficial
embodiment of the invention thus enables the arrangement to be
re-used.
[0013] According to another beneficial feature of the invention,
the arrangement is characterized in that the coupling means has an
internally threaded coupling end for connection with an externally
threaded end of the reinforcing and/or anchoring element. The
coupling means and the injection pipe comprise a single entity,
which affords the advantage of greater mechanical strength than
would otherwise be the case, eliminates the risk of these
components being separated from each other after having been
screwed together and the entire arrangement shall be unscrewed from
the anchoring point, and enables the arrangement to be handled more
practically from a general aspect. The coupling means is
beneficially also designed so as to facilitate the release of the
arrangement from the surrounded injected material upon completion
of the material injection phase and subsequent to hardening of the
material. This can be achieved by causing the coupling means, which
is typically cylindrical, to taper conically to a slight extent in
a direction inwardly in the hole, or to coat the outer surface of
the coupling means with Teflon for instance, or with some readily
elastic or resilient material. Other coupling means may,
alternatively, be greased. A combination of these proposed
alternatives is also feasible.
[0014] According to one feature of the arrangement, the seal has
the form of a sleeve disposed around the injection pipe. The sleeve
will then function beneficially as an inner seal defining wall,
wherewith the seal is caused to expand radially outwards between
the outer wall of the injection pipe and the inside of the hole for
sealing abutment with both outer wall and inner surface.
[0015] According to one variant, the seal has the form of a
mechanically expandable sleeve.
[0016] According to another variant, the seal has the form of a
sleeve that includes double walls and that can be expanded by
injecting a pressurised medium into the sleeve between said walls.
Consequently, the inventive arrangement also includes means for
delivering pressurised medium to the seal.
[0017] According to a first embodiment, the check valve is disposed
at the front end of the injection pipe. This embodiment is
beneficial when the reinforcing and/or anchoring element is a solid
rod and when the injection medium shall be pressed out into the
hole behind the coupling means but in front of the seal.
[0018] According to a second embodiment, the arrangement is
characterized in that the coupling means includes an axially
extending and through-passing aperture and is designed to enable it
to be coupled to a tubular element that forms said reinforcing
and/or anchoring element; and is further characterized in that the
check valve functions to regulate the supply of injection medium
from the injection pipe via the aperture in the coupling means and
through said tubular element and out at the front end thereof. The
benefit afforded by this embodiment is that the injection medium
can be fed out at a point much further into the hole, depending on
the length of the tubular reinforcing and/or anchoring element, and
there penetrate into the cracks etc. present in the rock wall.
[0019] A further benefit achieved by this embodiment is that the
tubular element forming the reinforcing and/or anchoring element
may consist of a drill rod that includes internal channels and also
a drill bit for boring said holes, wherewith the check valve
regulates the supply of injection medium from the injection pipe
via the aperture in the coupling means, through said drill rod and
out through the drill bit.
[0020] The inventive method of injecting and securing a reinforcing
and/or anchoring element in a rock wall comprises the following
method steps: [0021] inserting a reinforcing and/or anchoring
element in a hole in the rock wall with said element coupled to an
injection means which constitutes a separate entity or unit and
includes means for coupling the injection means to a reinforcing
and/or anchoring element, an injection pipe which is connected to
said coupling means at a front end facing inwardly in the hole and
which is also provided with connecting means for connection to an
injection medium supply means, wherein the arrangement also
includes a check valve for co-action with the injection medium and
an expandable seal; [0022] expanding the seal on the injection
means so as to prevent injection medium injected into the hole from
exiting from the hole during and after the medium injection phase;
[0023] delivering injection medium to the hole via said injection
arrangement and said check valve; [0024] terminating the injection
phase and allowing the injection medium to harden; [0025] causing
the expandable seal to return to its non-expanded state after
termination of the injection phase and allowing the injection
medium to harden at least partially; and [0026] removing the
injection means as a unit.
[0027] This method affords the benefits that no part of the
injection means will be left in the hole, therewith greatly
reducing the risk of corrosion in the hole and also enables the
injection means to be re-used as it is.
[0028] Another beneficial feature is that the hole is drilled with
the aid of a drill rod provided with a drill bit where said drill
rod later forms the reinforcing and/or anchoring element, and that
drilling takes place when the injection means has already been
coupled to the reinforcing and/or anchoring element. According to
the inventive method, the injection phase can be carried out via a
through-penetrating aperture in the coupling means and also via an
internal channel in the drill rod and out into the hole via the
drill bit fitted to the front end of the drill rod.
[0029] According to the inventive method, the injection medium is
beneficially injected at an overpressure, wherewith the hole is
first filled with injection medium which then penetrates into any
cracks present in the surrounding rock, said injection means
opening out into the hole so as to thereby seal the cracks. Among
other things, this avoids the risk of the injected medium solely
forming a plug in the hole without being anchored to the
surrounding rock. As earlier mentioned, any plug that forms can
easily loosen from the sides of the hole and therewith fall out of
the same. By overpressure is meant in this case a pressure of at
least 1 bar and normally between 1-2 bar and up to 100 bar or even
at a higher pressure if necessary. With regard to sealing the rock,
the pressure applied must also be adapted to the nature of the rock
into which the medium is injected. The rock is sometimes of a poor
quality, i.e. very porous and perhaps also water-conducting,
wherewith a high pressure is required in sealing the rock, in some
instances up to several hundred bar. A high injection pressure
eliminates the risk of pockets of air and water. The reinforcing
element is also anchored more securely in the rock.
[0030] The magnitude of the pressure required will also depend on
the extent of the rock covering above the area to be sealed, in
other words on how much rock is located above this area, and will
also depend on the static pressure exerted by the ground water. The
ground water pressure will also be high in the case of rock that
includes an open-air lake, therewith requiring the application of a
high injection pressure.
[0031] Another beneficial feature afforded by the inventive method
is that the injection means can be re-used for the injection and
anchoring of a new reinforcing and/or anchoring element in the rock
wall. This clearly constitutes an economic benefit in comparison
with earlier known arrangements of the one-time-use only type.
[0032] Finally, a further beneficial feature afforded by the
invention is that subsequent to removing the injection means the
reinforcing and/or anchoring element will have a free end located
within the hole sealed with the injection medium, this free end
being available for the attachment of further equipment. This is of
enormous benefit. Examples of equipment that can be secured with
the aid of an anchoring element include ventilation systems in
tunnel roofs, ventilation ducts, fans, blowers and lighting
equipment. The anchoring element can also be used to hang-up other
equipment used in tunnelling practices for instance. Further
examples include devices for fastening reinforcing nets, protective
nets against stone and rock slides, etc. The anchoring element can
also be used solely for securing a device that pressurizes the rock
as it is.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The present invention will now be described in more detail
with reference to the exemplifying embodiments illustrated in the
accompanying diagrammatic drawings, in which
[0034] FIG. 1 is a diagrammatic sectioned side view of a first
embodiment of an inventive arrangement that includes a first
variant of the expandable seal with the seal shown in a
non-expanded state;
[0035] FIG. 2 is a diagrammatic side view corresponding to FIG. 1,
but showing the expandable seal in an expanded state;
[0036] FIG. 3 is a diagrammatic sectioned side view of a second
embodiment of an arrangement according to the present invention,
showing a second variant of the expandable seal with the seal in a
non-expanded state;
[0037] FIG. 4 is a diagrammatic side view corresponding to FIG. 3,
but showing the expandable seal in an expanded state;
[0038] FIG. 5:1-8 illustrates the method of using an arrangement
according to the first embodiment;
[0039] FIG. 6: 1-6 illustrates the method of using an arrangement
according to the second embodiment;
[0040] FIG. 7 is a diagrammatic sectioned side view of a third
embodiment of an arrangement according to the present invention,
with the expandable seal shown in a non-expanded state;
[0041] FIG. 8 is a diagrammatic side view corresponding to FIG. 7,
but showing the expandable seal in an expanded state; and
[0042] FIG. 9 is a diagrammatic sectioned side view illustrating an
example of use in accordance with the inventive method.
[0043] Those components shown in the figures that are common to the
various embodiments have been identified with the same reference
signs.
DETAILED DESCRIPTION OF THE INVENTION
[0044] FIGS. 1 and 2 illustrate a first embodiment of an
arrangement 1 for injecting and securing a reinforcing element
and/or anchoring element 2 in a rock wall 3, in accordance with the
present invention. For the sake of simplicity the arrangement will
be referred to solely as an injection means in the following text.
Correspondingly, the reinforcing and/or anchoring element 2 will be
referred to solely as the reinforcing element in the following
text. This should in no way be understood as limiting the scope of
the invention. The reinforcing and/or anchoring element 2 may also
consist of solid iron material or a hollow tube.
[0045] FIGS. 1 and 2 show a first embodiment of the injection means
1 coupled to the reinforcing element 2, wherewith the mutually
coupled members are together inserted into a hole 4 in a rock wall
3. The injection means constitutes a separate unit. The illustrated
first embodiment of the injection means 1 includes a first variant
of a packer-type expandable seal, namely a mechanically expandable
seal 5. The injection means 1 also includes means 7 for connection
to a means (not shown) for supplying an injection medium 8. This
supply means preferably includes a pump, which enables the
injection medium to be supplied at an overpressure. A suitable
injection medium is a cement grout or a chemical liquid. The
connection means 7 is provided at the end of an injection pipe 9
remote from the hole, this end also being called the outer end. A
check valve 10 is provided in connection with the front end of the
injection pipe line, i.e. the end proximal to the hole 4. This
check valve may be of a known kind, e.g. of the kind known from
prior publication WO 99/56001. The check valve 10 shall, in any
case, be able to withstand the pressure at which the injection
medium is injected, so as to ensure that the injection medium will
not flow back out through the valve. The injection means 1 also
includes coupling means 15 on the front end of the injection pipe.
This coupling means has an internal thread 16 and is screwed to an
externally threaded end 17 of the reinforcing element 2. The
reinforcing element 2 is thus of a typical kind provided with an
external thread.
[0046] The hole 4 in the rock wall 3 may be an existing hole or a
hole that was made particularly for the purpose concerned.
[0047] FIG. 1 shows the injection means 1 and the reinforcing
element 2 when they have just been inserted into the hole 4, prior
to expansion of the seal 5. This figure also corresponds to FIG.
5:2.
[0048] FIG. 2 shows the injection means 1 when the seal 5 has been
caused to expand and therewith seal against the inner wall of the
hole 4. As will be seen, the seal 5 of this embodiment has the form
of an expandable sleeve disposed around the injection pipe 9. The
seal 5 is made of an elastic, resilient, springy material or some
other yieldable material, such as rubber, so as to enable its shape
to be changed. The seal is caused to expand mechanically with the
aid of a known, separate clamping tool 20, which is shown in FIG.
5:3. The tool 20 exerts a force on the outwardly facing end of the
seal 5 and, by virtue of an abutment means or stop 18 provided at
the inner end of the seal that prevents the seal from moving
inwardly along the injection pipe 9, the seal will be compressed
axially and therewith expand radially so as to come into sealing
abutment with the inner wall of hole 4. Provided at the outwardly
facing end of the seal is some type of locking device that prevents
the seal from sliding back outwardly and return to its non-expanded
state subsequent to removing the clamping tool 20. The locking
device will preferably be comprised of locking washers or plates 19
in the form of a known particular type of spring washer.
[0049] FIGS. 3 and 4 illustrate a second embodiment of an
arrangement 1 for injecting and securing a reinforcing element
and/or anchoring element 2 in a rock wall 3, in accordance with the
present invention. In the case of this second embodiment, the
injection means differs from the injection means of the first
embodiment, in that the expandable seal consists in this case of a
second variant in the form of a pneumatically or hydraulically
expandable seal 50. The seal 50 thus has the form of a sleeve which
includes double walls and which can be expanded with the aid of a
pressurized medium delivered into the sleeve, i.e. into the space
between said walls. According to this second embodiment, the
injection means therefore includes means for delivering said
pressurized pneumatic or hydraulic medium 58. Thus, in addition to
the means 7 for connecting the injection means to an injection
medium supply means, as shown at 8, the injection means also
includes means 51 for connection to a pneumatic or hydraulic
pressure source, not shown. A connecting line 52 is provided
between the connection means 51 and the space between the walls of
the sleeve-like seal, so that pressurized medium is transported to
the space between the double walls and therewith cause the seal 50
to expand; see FIG. 4. Other parts of the injection means are the
same as those in the first embodiment, with the exception that the
use of locking washers or plates at the outwardly facing end of the
seal is not necessary in the case of the second embodiment.
Nevertheless, the material from which the seal is made is an
elastic, springy material or a material that is non-rigid, such as
a rubber material, so that its form can be changed.
[0050] The coupling means 15 in both embodiments has the form of a
truncated cone that has an internal thread 16. The conical shape of
the coupling means is primarily intended to facilitate release of
said means from the injected material 8 subsequent to said material
having hardened, whereafter the injection means 1, including the
coupling means 15, shall be removed completely from the hole 4. The
coupling means 15 may also be treated on its outer surface with a
removal facilitating means, for instance with a Teflon coating or a
coating of some elastic material. Alternatively said outer surface
may be greased.
[0051] The inventive method will now be described with reference to
FIGS. 5:1-8 and 6:1-6, these figures being related to the first and
the second embodiment respectively.
[0052] FIGS. 5:1 and 6:1 illustrate respectively a rock wall 3 in
which a hole 4 has been drilled, this being the normal procedure.
FIGS. 5:2 and 6:2 illustrate respectively the insertion of a
reinforcing and/or anchoring element 2 into the hole 4 in the rock
wall 3. The element 2 is coupled to an injection means 1 which
constitutes a separate unit and includes a means 15 for coupling
the injection means 1 to the reinforcing and/or anchoring element
2, connecting means 7 being intended for connection to a means for
the supply of injection medium 8, an injection medium check valve
10 and an expandable seal 5 and 51 respectively.
[0053] FIG. 6:2 also shows the expansion of the seal 50 of the
injection means, which in this case is achieved with the aid of a
delivered hydraulically or pneumatically pressurized medium, such
as water or air for instance. FIG. 6:3 shows the appearance of the
expanded seal 50. The seal 50 is in sealing abutment with the
injection pipe and all the walls of the hole and prevents injection
medium injected into the hole 4 from flowing out of the hole during
and after the injection phase. Correspondingly, FIG. 5:2 shows how
the first variant of seal 5 is expanded mechanically with the aid
of a tool 20.
[0054] FIGS. 5:4 and 6:3 illustrate delivery of injection medium 8
to the hole 4, via said injection means I with its coupling means 7
for connection to the injection medium delivery means, and the
injection pipe 9 and the check valve 10. The cavity in the hole 4
and around the reinforcing element 2 is filled with injection
medium 8 and when the cavity is full, the injection medium is
pressed out into rock cracks and fissures that open into the hole
4, by virtue of the overpressure to which the injection medium is
subjected.
[0055] Respective FIGS. 5:5 and 6:4 show the injection means 1 and
the hole 4 after completion of the injection phase, while the
injection medium 8 is allowed to harden.
[0056] FIG. 6:4 also shows how the expandable seal 50 is caused to
return to its non-expanded state after completion of the injection
phase and after the injection medium 8 has hardened at least
partially. This is achieved by either returning the pressurized
expansion medium to the pressure source or releasing it to the
surroundings. With regard to the mechanically expandable seal 5,
FIG. 5:6 shows how the seal is allowed to return to its
non-expanded state by removing the locking washers 19.
[0057] Respective FIGS. 5:7 and 6:5 illustrate the removal of the
injection means 1, comprising the means 15 for coupling the
injection means to the reinforcing and/or anchoring element 2, the
check valve, seal and injection medium delivery means. The
injection means can thus be released from the reinforcing element,
by unscrewing the coupling means 15 from the reinforcing element
2.
[0058] Finally, respective FIGS. 5:8 and 6:6 illustrate the hole 4
subsequent to the removal of the injection means. As will be
evident from the figures, the reinforcing element 2 leaves in the
hole 4 a free end 17 which can be used to secure diverse equipment,
as earlier described. Naturally, it is also possible to fill the
remainder of the hole with injection medium or with some other type
of filler if so preferred.
[0059] FIGS. 7 and 8 illustrate a third embodiment of an injection
means 1 and the attachment of a reinforcing element and/or
anchoring element 62 in a rock wall 3, in accordance with the
present invention. This embodiment differs from the two earlier
embodiments, primarily by virtue of the fact that the coupling
means 65 is also hollow, i.e. provided with a through-passing
aperture or bore. In this case, the check valve 10 is located
between the front end of the injection pipeline and the aperture in
the coupling means 65. When also including a hollow reinforcing
element 62, this enables injection medium to be fed right up to the
innermost end of the reinforcing element, where the medium is then
pressed out into the hole 4. It is then possible, in particular, to
allow the reinforcing element 62 to comprise a drill rod that has
an internal channel, i.e., in principle, a thick-walled pipe which
is fitted with a drill bit 63 at its front end. This embodiment can
thus be used to first drill the hole 4 in the rock wall 3, prior to
said injection phase and the affixation of the reinforcing element
62. The coupling means 65 is also conveniently provided with an
internal thread 66 in this case, for connection with an external
thread 67 on the drill rod 62.
[0060] In the case of the third embodiment, the expandable seal 60
is comprised of a mechanically expandable seal.
[0061] This third embodiment also includes means 7 for the supply
of injection medium 8. This supply means may consist of a swivel
device. The injection pipe 9 includes an extension 68 along the
supply means. This extension is intended for connection to a
drilling machine and is preferably solid. The hole is drilled by
relatively slow rotation of the drill rod, at a speed of about
100-200 rpm, preferably combined with a certain amount of impact
energy.
[0062] In order to achieve rotation of the drill rod 62 via the
injection pipeline and its extension 68, it is necessary to mount
the injection medium supply means 7 on the injection pipe in a
manner to prevent rotation of said supply means as other components
rotate. In this connection, it is convenient to use a separate
expansion device 69 for the seal 60, this expansion device being
the subject of an individual, separate patent application filed on
the same day as the present application and by the same applicant.
This expansion device 69 may be placed around the injection pipe 9
in a manner which prevents it from rotating with the injection
pipe. This expansion device is based on a piston-cylinder-device
and is controlled either pneumatically or hydraulically.
[0063] The arrangement and method according to this third
embodiment function in accordance with the following. The drill bit
63, which is of a disposable type, a so-called lost bit, a drill
rod 62, the injection means 1, the injection medium supply means 7
and preferably also the separate expanding device 69 are assembled
together and connected to a drilling machine. Drilling of the hole
is commenced, alternatively there is used an existing hole of some
kind, and the arrangement is inserted as far as possible into the
hole before starting the drilling phase. Drilling is terminated
when a desired bore depth has been reached, and the seal 60 is then
expanded so that the entire device will be held firmly in the hole
by means of friction. The injection medium 8 is then delivered at
an overpressure through the arrangement and out into the hole, via
the drill bit 63 which includes suitable channels to this end. The
injection phase is terminated and injection medium allowed to
harden. The expandable seal 60 is then caused to return to its
non-expanded state, by releasing the pressure in the expansion
device 69. The entire arrangement can then be loosened from the
drill rod 62 by unscrewing the coupling means 65 from the end of
the drill rod and the entire arrangement can be removed optionally
for use in a further hole. The drill bit thus remains in the hole
together with the firmly injected drill rod and functions as a
reinforcing element and can also be used as an anchoring element
when it has a free end similar to that obtained in the other
described embodiments.
[0064] It should be added that although the injection pipe and the
coupling means of all illustrated embodiments have been shown as
being a single unit it will be understood that this is not a
requirement of the actual concept of the invention.
[0065] It will also be understood that it is, of course, also
conceivable to include a variant of the invention that is adapted
for a non-hollow drill rod which is connected to the coupling means
and used to drill the hole and then function as a reinforcing or
anchoring element. Such a variant would then include coupling
means, check valve and seal constructed in accordance with the
principle illustrated in the two first embodiments, while the
injection medium supply means and the hole sealing expansion means
must be designed to permit rotation of other components,
corresponding to that illustrated in FIGS. 7 and 8
respectively.
[0066] FIG. 9 shows how the free end 17 of the reinforcing element
2 in the hole 4 can be used to attach equipment. In this case there
is included a threaded rod 30 that carries a washer 31 and a nut 32
which is used to tension the rock itself by tightening the nut
and/or for fastening, e.g., a reinforcing net or the like. An
internally threaded sleeve 33 of a known kind is used as a coupling
means between the reinforcing element and the threaded rod.
[0067] It will be understood that the invention is not restricted
to the illustrated exemplifying embodiments thereof, and that
modifications and changes can be made in various ways by the person
skilled in this art within the scope of the accompanying
claims.
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